Method of transporting oil long distances.



v. A. E. ROBERTS & A. L. EMERY. METHOD OF TRANSPORTING OIL LONG DISTANGES.

APPLICATION FILED NOV. 22, 1910.

1,016,958. '7 Pfinted Feb 13,1912.

gm f/(fiam METHOD OF TRANSPORTING OIL LONG DISTANCES.

Specification of Letters Patent.

Patented Feb. 13, 1912.

Application filed. November 22, 1910. Serial No. 593,737.

To all whom it may concern:

Be it known that we, ALFRED E. ROBERTS and ARTHUR L. EMERY, citizens of the United States, residing, respectively, at Sausalito and Palo Alto, in the counties of Marin and Santa Clara and State of California, have invented a new and useful Method of Transporting Oil Long Distances, of which the following is a specification in such full and clear terms as will enable those skilled in the art to construct and use the same.

This invention relates to a method of increasing the flow of and economy of working of long oil pipe lines.

An object of the invention is to increase the amount of oil a given pipe line will carry, and to provide for a more uniform heating of the oil in the pipe line, than is possible with the systems now in use.

A further object of the invention is to make use of the existing pumping plants, as far as is possible, to distribute heat along the entire line of pipe and thus lessen the viscosity of the oil and reduce the pressure necessary to move it.

It will be understood by those skilled in the art in the transmission of oil through long pipe lines that very small differences in the viscosity of the oil being moved make great differences in the pressure necessary to force it along. For example, if the pipe line has been allowed to get cold and all the pumps have been stopped a pressure of more than a thousand pounds per square inch will not move a heavy oil, while if heat be applied to the oil it can be moved throughout the pipe line with a pressure of about 800 pounds per square inch.

Another object of the invention is to provide for the heating of the oil at places where it may be. necessary owing to the short bends in the pipe, or to the fact that the pipe runs through a cold valley where frost is liable to cause the oil to become so cold as to interfere with the flow of the oil.

In the drawing, in which the same numeral represents the same portion throughout, Figure 1 is a side elevation of a section of pipe line and the pumping plants used in connection therewith, and Fig. 2 is a side elevation of one of the heaters used showing a conventional view of a thermostat used to control the heat applied to the pipe line. The numeral 1 represents the ground level, 2 the pipe line and 3 represents a central power station. Along the line of pipe there may be a number of power and pumping stations 4, said stations being usually installed at a distance of about 14: miles apart. Each of these stations may be supplied with power from an electrical transmission line 5 supported upon the usual poles 6, and in addition each station may be equipped with a boiler and furnace the chimney of which is shown at 7. Along the pipe line at such intervals as may be deemed necessary between successive pumping stations there are a plurality of electric heating elements 8, each heater receiving current from a wire 9 connected with the power line, and returning by way of the pipe line 2. It is to be observed that an important feature of this invention lies in the more uniform and equal heating of the oil throughout the pipe line, and this object is accomplished by providing an electrical heat measuring device 10 at each heater, thus turning on or shutting off current whenever it may become necessary, without attention on the part of the operatives.

Now it will be understood by those skilled in the art that it is necessary to heat the heavy oils found in California to such a temperature as to reduce the viscosity thereof to such a point as to make the pressure required to send them through the pipe lines low enough to be within the ultimate strength of the pipe used, and to make the transmission thereof practicable, since the pressure might easily run up so high as to make the profitable transmission of the oil impossible. Now it will be further understood that fuel must be used for the purpose of heating the oil in the present plants, which fuel is taken at the several pumping plants along the line from the oil being transported, thus reducing the total quantity the pipe line can carry by exactly the amount of oil so used. This amount of oil is about 10% of the total oil shipped in a pipe line of about 160 miles. Another consideration entering into the roblem is that in the present plants it has been customary to use simple engines using about 33 pounds of water per hour per horse power. The excess heat of the simple engine plant over that used in a central power station consuming about 11 pounds of water per hour per horse power is used to heat the oil in its passage through the pumps. The investment in such plants as this is too great to alter all at once so that this system must be applied to existing systems as well as to new systems. Such stat-ions as those mentioned heat the oil to as a high a temperature as all of their waste steam will effect each 14 miles, but since the oil is heated much hotter than is actually necessary to overcome the viscosity thereof, it loses heat very much more rapidly than it would if it was heated only a few degrees above the temperature of the ground surrounding the pipe. I

The intention, therefore, with this system, is to heat the oil at such a considerable number of places along the line as to make possible an increase in temperature of all of the oil a few degrees. It is also to be noted that where the oil is heated only once in 14 miles its heat is all lost after it has traveled a mile from the pump house, this rapid loss in heat being due to the fact that the oil and ground are at such considerable distances apart in temperature as to make the heat losses very much more rapid than if the oil was heated only a few degrees above the heat of the ground. In existing systems this method of handling the oil may be employed by the installation therein of low pressure power generating units which will operate on the steam from the simple engines now in use, and which will then leave heat enough in the waste steam to heat the oil sufliciently to pass through the pumps easily. The power thus generated is distributed over the pipe line to heat the oil at a great number of places. How this will work out actually is shown by the fact that the temperature of the exhaust steam from a simple engine pounds absolute pressure is 311 degrees F. or 261 degrees above the average temperature of 50 F. of the ground, while the temperature of steam at 20 pounds absolute, as it comes from a low pressure power unit is 230 degrees, or 180 degrees F. above the ground, thus leaving available about two thirds of the heat leaving the pumping plant for heating purposes at the pumping station, while one third is available for heating at places along the pipe line. This will mean that with the losses of electrical transmission and heating 91% of the heat will be available over the entire line to raise the temperature of all of the oil a small amount. The result of this heating will be that the oil will flow much easier, thus enabling a larger quantity to be pumped through the line, without an increase of power. An advantage gained here is also to be seen when it is considered that with a dead line the heating at the station does no good at all in the parts of the line between the stations, and the starting pressure must be very greatly in excess of the regular working pressure.

The above description applies to plants which are now in use and to which are added power units for the production of transmissible heat. The above results in an economy, but there may be a further economy in the installation of a central power station as will be seen upon an examination of the price of oil at the wells and at the market. This is shown by the fact that oil at the well is worth about L0 cents per barrel, and on account of the fact that transportation is hard to get there is nearly always a large surplus tending to hold the price down at the wells. The transportation charges for about 160 miles amount to 12 cents per barrel, making a total cost to the owner of the oil of 52 cents per barrel, while the selling price of the oil is about $1.00 per barrel, leaving a profit of 48 cents per barrel. Now from the above figures it will be seen that the farther the oil is shipped the more costly is the oil which is used to heat the oil in the pipe line, to say nothing of the fact that every barrel of oil used along the line reduces the total carrying capacity of the line by just exactly that amount, which amount will be about 10 per cent. in a line 160 miles long. Therefore, if a central power plant be installed adjacent the wells where there is a plentiful supply of oil, and from which power is sent along the line to the various pumping stations and the heaters installed along the line, two economies result. First. The price per barrel of the fuel used is less than one half the selling price of the product after it has been transported, while it is possible to use steam engines at a central station which will generate one horse power for each 11 pounds of water evaporated, whereas the present pumping stations use 33 pounds of water per horse power per hour. This will make possible the generation at the oil wells of more than seven and one half times the power possible with the simple engine and present heating system at the same cost of oil. Since electrical power can be transmitted a distance of 160 miles with a loss of less than ten per cent. it thus becomes possible to have a very considerable margin of power to ship the oil, and the mere changing of the power plant to the oil fields means that the amount ofoil delivered is about 11 per cent. more since none is taken out along the line, the above figures being for a line of about 160 miles. This gain is still more apparent when it is considered that the loss on oil where it is stored in open tanks is very considerable to say nothing of the loss in interest and the storage charges on the oil. It is also intended to use for heating the oil such electrical resistances as are easily removed and repaired, and which can be readily immersed in the oil thus making possible the more uniform heating of the entire body of oil without mechanical agitation. A necessity for this manner of heating will be seen when it is considered that the oil is a very poor conductor of heat and often the core of the oil with the ordinary steam heater is very much colder than the temperature at which its viscosity disappears.

Another advantage of this system of heating and power transmission is that it makes possible the flexible control of the power used in the line, all stations and heating elements being controlled from a central plant, and it also makes possible the increase in capacity of the pipe line in times when the oil is in great demand, additional power being purchased from the power companies dealing therein. It is to be further noted that while the cost of transportation by way of the pipe line for the distances mentioned herein is only 12 cents, the price for shipment by rail for the same distance is 42 cents for the same amount of oil. The result of this is that even if the total cost of pipe line transportation was increased there could by no possibility be an increase of the amount to such an extent as would result in a greater cost than rail shipment, since the pipe lines would break down long before such an amount of power as that had been applied to them. It is also to be noted that it is necessary to heat the oil to about 110 degrees F. in order to get it to pass through the valves, but this is the maximum temperature of the mass of oil while the core is very much colder. In the present invention the intention is to heat the mass of oil more uniformly and to a less degree, and if necessary use a positive method of forcing it to the suction valves of the pumps.

Having thus described our invent-ion what we claim as new and desire to secure by Letters Patent of the United States, is as follows:

1. In a method of transporting oil through long pipe lines, forcing the oil lnto the pipe line at a plurality of distant stations, and suitably heating the oil transported at a plurality of places between the stations by means of electric power generated at one of said stations, substantially as described.

2. In a method of transporting oil through long pipe lines, forcing the oil into said pipe line at a plurality of diflerent pumping stations suitable distances apart and heating the oil so transported at a plurality of different places between the pumping stations from electric power generated at a central station, substantially as described.

3. In a method of transporting oil through long pipe lines, forcing the oil into said pipe line at a number of successive stations suitable distances apart, and electrically heating the oil at a plurality of different places between the successive pumping stations, substantially as described.

4. In a method of transporting oil through long pipe lines, forcing the oil into said pipe line at suitable successive stations, and electrically heating the oil at a plurality of successive places between the pumping stations from current generated at one of said sta tions and controlled at a number of places, substantially as described.

5. In a method of transporting oil through long pipe lines, pumping the oil into said pipe line at a number of distant stations, supplying power to each of said pumping stations from a central station, and heating the oil at a number of points between succesive stations from electric power generated at the central station, substantially as described.

6. In a method of transporting oil through long pipe lines, pumping the oil into the pipe line at a series of suitably distant stations, electrically heating the oil so transported at a plurality of places between successive stations, heating the oil at each station to such a temperature as to enable the pumps to handle the same, and regulating the heating between stations so that the oil will remain a few degrees only above the temperature of the ground, substantially as described.

7. In a method of transporting oil through long pipe lines, pumping the oil into the pipe line at a plurality of electrically operated pumping stations suitable distances apart, electrically heating the oil transported at a plurality of places between stations, and heating the oil at each station to such a temperature as will enable the same to be readily handled by the pump, substantially as described.

8. In a method of transporting oil through long pipe lines, forcing the oil into said pipe line at a plurality of electrically operated pumping stations, electrically heating the oil so transported at a plurality of places between stations, and automatically regulating the amount of heat supplied at such places so that the temperature at any point will not exceed a few degrees above that of the ground, substantially as described.

9. In a method of transporting oil through long pipe lines, pumping the oil into said pipe line at a number of electrically operated pumping stations, electrically heating the oil at a plurality of different places between stations, automatically controlling the set our hands this 15th day of November amount of heat so delivered to the oil be- A. D. 1910, in the presence of the tWo sub- 10 tween stations and heating the oil at sucscribed Witnesses.

cessive stations to such a temperature as ALFRED E. ROBERTS. 5 will permit the same to be readily handled ARTHUR L. ENIERY.

by the pumping apparatus, substantially as Witnesses: described. M. F. MACDONALD,

In testimony whereof We have hereunto B. R. PUTNAM.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). 0. 

